This study is designed to identify approximately 30 infants with congenital viral infection. The detection program consists of screening newborns with urine cultures (and other cultures where appropriate) for CMV and herpesvirus. These infants will then undergo complete medical, developmental and immunologic evaluation. The aim is to define the immune status of these infants and relate it to the degree of impairment. Immunologic evaluation will be in two areas: 1) General immune status, and 2) Host-virus interaction in chronic virus excretors. The studies will include: 1) response of peripheral lymphoid cells to PHA, PWM and allogenic cells, 2) measurement of immune globulins, 3) measurement of lymphocyte mediator substances, 4) a search for blocking antibody, 5) evaluation of completed levels, 6) measurement of phagocytic function, 7) measurement of CMV neutralizing salivary IgA, and, 8) assessment of PHA and PWM response differences in adults as opposed to infants. These studies are being undertaken to add knowledge about the natural history of congenital virus infections, to attempt to shed new light on the enigmatic problem of virus excretion in the presence of high titers of humoral antibody, and to develop new therapeutic approaches using chemotherapy and possibly immunotherapy.